Some motion detectors used in modern security systems may be defeated by placing a masking material on the face the detector. Due to this, some motion detectors incorporate an antimasking system to detect such events. Motion detectors with antimasking capabilities may be used in high-security alarm systems. Motion detectors with antimasking capabilities typically incorporate an active infrared detection system to detect masking attempts. Infrared detection, however, has its own drawbacks and may be defeated by someone knowledgeable about the device.
In addition, false alarms may be generated by motion detectors. The false alarms may be generated based on detection of domestic pets, insects, birds, and others in close proximity to the motion sensor. False alarms may also be generated by the antimasking detection. For example, antimasking devices using infrared sensors may be triggered based on detection of light sources and light-reflective objects within a detection area such as sunlight reflections, bugs on the face of the detector, and others. As a consequence, motion detectors that include infrared antimasking capability may be prone to generating false alarms.